Automatic sliding doors used in high performance elevators must meet various operating regulations. For example, to protect against wedging, it is required that a maximal movement energy of all parts connected together mechanically do not exceed a preset maximum value (for example 10 joules) at a mean closing speed. This requirement sets an upper limit value for the mean closing speed. On the other hand, short door closing times are a prerequisite for good transport performance in high performance elevators. The mass of the elevator doors is related to the kinetic energy of the elevator door system, and, thus, needs to be determined.
Similarly, a control module in the elevator door system controls the motion of the elevator door using an electric motor as an actuator. To improve ride comfort of passengers, it is desirable to operate the elevator door movement smoothly. Hence, the control module needs to reduce vibration and noise while opening and closing the elevator door. The control module controls the motion of the elevator door according to at least the mass of the elevator door, which also necessitates the knowledge of the mass of the doors.
Different methods have been used to determine the mass of the doors in the elevator system. For example, one method weighs the doors of the elevator system before commissioning the elevator system. However, the weight of the door can change over time in many cases. For example, customers may change the decoration of the doors that affect its weight. Thus, there is a need to determine the mass of the elevator door online during the operation of the elevator system.
Another method estimates the mass of the elevator door based on a linear static model, which represents the relationship between a translational acceleration of the door and a torque of the electric motor moving the door. However, the linear static model fails to capture various physical factors affecting the movement of the door. For example, the linear static models do not take into consideration friction forces affecting dynamics of the elevator door system, and thus can produce an inaccurate estimation of the door mass. In addition, the existing methods generally estimate the mass of the elevator doors offline.